JA Solar has received an order for its commercially available mass-produced multi-cut-cell-based TOPCon module for a South Korean project
This module, with the help of a gapless cell-to-cell stringing process and modified cell layout, creates a ‘full-screen’ design
It also optimizes the lamination process with the so-called Composite Structure Enhancement (CSE) technology
Leading solar PV manufacturer JA Solar has recently received a supply order for a 410 MW South Korean utility project. The company will supply its latest DeepBlue 5.0 TOPCon module, which was officially launched in H1 2025 and entered mass-scale production in Q4 2025.
According to the company, this commercially available modules incorporate multiple new features at the wafer, cell, and module levels. However, our focus for the purpose of this article will be limited to module-level improvements only.
The module maker states that it selected the 1/3-cutting route following an in-house analysis of internal power loss, process yield, and cutting loss across multiple cell-cutting methods, including half-slice (1/2), three-slice (1/3), four-slice (1/4), and others. Equipped with 198 (3 × 66) cells, this module features dimensions of 2,382 x 1,134 mm. Unlike the conventional multi-cut-cell layout, featuring 2 symmetrical substrings (6 × 33) under each bypass diode (typically placed across the middle of the long side of a PV module), it adopts a 66-cell-based 3-substring layout. The 2 substrings are laid up in back-to-back configurations covering 2/3rd of the area across the long side of the module, while the 3rd one uses the rest of the bottom area. Regarding cell-to-cell stringing process optimization, the company uses a ‘gapless flexible interconnection’ technology that overlaps consecutive cells, increasing the utilization length of each string and module edges by 15 mm and more than 25 mm, respectively. According to the company, this ‘full screen’ design increases active cell area by 1.82%, delivering up to 20 W of additional power and a 0.56% absolute efficiency gain, bringing 670 W and 24.8%, respectively.
In addition to layout customization, JA Solar also addressed potential reliability issues for long-term field operations. The company uses an additional rear-side encapsulant in conjunction with standard front- and rear-side films between the cell matrix, a technology it calls Composite Structure Enhancement (CSE). It maintains cross-sectional consistency of the laminated component from the module’s edge to the center, enhancing resilience against long-term damp-heat environmental stressors. Regarding rear-side glass breakage, the company relocates the rear glass junction box termination holes into a triangular pattern. Instead of placing 3 bypass diodes across the middle of the module, this distributed design provides higher mechanical strength (unquantified). This module also features short-side frames with multiple drain holes that efficiently flush away loose dust from rain or cleaning water, mitigating the risk of hotspots. Under the edge shading from the very next module row, typically common in portrait-configured ground-based installations, its gapless cell layout delivers up to 67% of the rated power compared to 50% of half-cut cell-based counterparts, the company claims. Fewer current leakage paths inherent in the TOPCon cell structure, compared with back-contact (BC) peers, also help the module perform better in low-light conditions, such as early morning, late afternoon, or overcast days.
